The Internet facilitates the sale of goods or services by many different vendors. To purchase goods or services, a consumer often must create an account on many different market sites, and log into each one to peruse the goods and services offered. This approach is time intensive, and it limits the number of markets with which a consumer can interact. As an alternative strategy, a consumer may rely on a service that aggregates sale information from a variety of market sites. This approach is still time intensive, as a search can return thousands of listings and a consumer must examine each to determine whether the goods or services meet the consumer's specifications.